Final answer:
A reference group's influence is strongest when the use of the product is visible to the group. Reference groups, like athletes or peers, provide a standard for behavior and establishing social norms, particularly in visible consumption situations.
Step-by-step explanation:
Among the given options, a reference group's influence will be strongest when the use of the product or brand is visible to the group (A). This scenario falls under the social studies branch, particularly within the realm of consumer behavior and marketing. Reference groups exert a significant impact on individual's behavior, especially when members of the group can see the product being used since individuals often seek social acceptance or want to imitate others they admire within the group. These reference groups can include cultural centers, workplaces, or even family gatherings, and they help to establish social norms and behaviors. For instance, athletes may serve as a reference group for young individuals, inspiring their attire, activities, and interests.